1021797821244 has 192 divisors, whose sum is σ = 2582912102400. Its totient is φ = 313652072448.

The previous prime is 1021797821207. The next prime is 1021797821249. The reversal of 1021797821244 is 4421287971201.

It is a junction number, because it is equal to n+sod(n) for n = 1021797821193 and 1021797821202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1021797821249) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 141656982 + ... + 141664194.

It is an arithmetic number, because the mean of its divisors is an integer number (13452667200).

Almost surely, 2^{1021797821244} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1021797821244, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1291456051200).

1021797821244 is an abundant number, since it is smaller than the sum of its proper divisors (1561114281156).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1021797821244 is a wasteful number, since it uses less digits than its factorization.

1021797821244 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7484 (or 7482 counting only the distinct ones).

The product of its (nonzero) digits is 451584, while the sum is 48.

The spelling of 1021797821244 in words is "one trillion, twenty-one billion, seven hundred ninety-seven million, eight hundred twenty-one thousand, two hundred forty-four".